In modern poultry processing plants, chickens, turkeys, and other types of poultry raised for commercial slaughter are moved through a poultry processing plant where they are sequentially defeathered, eviscerated, cut up, and packaged for shipment to wholesale and retail consumers. In such a plant, it is common for the poultry carcasses to be suspended by their ankle bones or hocks from a shackle assembly. Most shackle assemblies in such machines have a pair of spaced depending stirrups that are configured to receive and releasably hold the hocks of the birds. In this way, workers can suspend birds from the shackles by slipping their hocks into the stirrups. The shackle assemblies, in turn, are mounted in spaced relationship to an overhead conveyor system that moves through the various processing stations of the poultry line. The shackles are spaced along the overhead conveyor so that birds suspended from the shackles are moved sequentially through the stations for serial processing of large numbers of carcasses.
As poultry carcasses are processed at the various processing stations of a poultry line, the carcasses are manipulated in various ways to accommodate each of the processing steps. In some of these stations, it is desirable and efficient to spread the legs of the carcass as far apart as possible to accommodate, for example, a blade, scraper, or other implement that operates on the carcass at the station. In many instances, the legs can be spread sufficiently with a spreader bar or the like as they move along the overhead conveyor. However, in a significant number of instances, and in particularly where the carcass is larger than average, the spreading of the legs will cause the hocks or the leg bones of the bird to break near the point at which they are suspended from the shackle stirrups. This is because most shackle stirrups used in modern poultry processing machines are designed to allow the legs of the bird to swing freely to and fro in the direction of conveyor movement while holding the hocks firmly in the lateral or side-to-side direction to restrict lateral movement of the legs. Thus, excessive spreading of the bird's legs, which can easily occur with a large carcass, will cause the hocks of the bird to bind within the stirrups, resulting in fracture or breakage of the hock or leg bone.
Breakage of hocks and legs in the manner just described is highly undesirable for a number of reasons. First, in many instances the broken hock or leg will allow the carcass to be pulled out of its stirrups as it is processed. This can clog the processing machinery and may require that the entire line be shut down to clean out the dislodged carcass. Further, even if the carcass does not become dislodged from its shackle, the broken bone renders the resulting chicken leg unmarketable for human consumption and it must be sold for some other less profitable use.
Accordingly, there exists a need for an improved poultry shackle assembly designed to receive and hold the hocks of a suspended bird in the normal way while at the same time permitting the hocks, when necessitated by spreading forces imparted to legs of the bird, to swing relatively freely without binding in the side to side or lateral direction as well as in the to and fro direction. Such a shackle should allow workers to hang the birds from their hocks in the normal way and should ensure that the birds remain properly oriented as they move into and out of the various processing stations. In addition, the shackle should accommodate rotation of the bird's legs to orient its knees outwardly, thus enhancing the spreadability of the legs and improving their orientations relative to the saddle of the carcass for more efficient processing. Finally, such a shackle should be simple, reliable, automatic in operation, and economical to manufacture and use in a poultry processing plant. It is to the provision of such an improved shackle assembly that the present invention is primarily directed.